Manual switchboard



Jan. 2, 1945. E. ENGQUlsT 2,366,604

` MANUAL SWITCHBOARD Filed Nov. 4, 1941 2 Sheets-Sheet l Patented Jan.2, 1945 ,zUNiTrEDr"STATES PATENT.. OFFICE, N N

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`ErikifSidtlrrlgtlliisty,Stockhohn;Sweden assiglb ortoTelefOnaktiebolaget L.` M. Ericsson,.StwkT u, '1mb-f Sweden, ,acompany ofsweden Applicationivoveihber 4, 1941, seria1No-41'z-,s42

In Sweden July 20, 1940 I 4 i 9 claims. p (o1. 179-;55)

The' invention relates t0 manual switchboards of the cordless class,that is to say, switchboards in which both the line wires for everysubscriber may be connected to an operators telephone set, cord circuitand the like by means of a plug which alternatively may be inserted intoa number of jacks arranged for every subscriber. Hitherto knownswitchboards of this class have been of a complicated construction andhave not made it possible easily to enlarge the switchboard whennecessary. The object of the invention is to eliminate thesedisadvantages and the invention 'mainly consists thereinthat the linewires for every subscriber are connected to two bare conductor wiresarranged at the jacks `belonging to the subscriber in such a manner thata spring connection between the wire and the plug is obtained.

` The invention will now be described more in` detail with reference tothe drawings attached, said drawings showing an embodiment of the4invention. Fig. 1 is an elevation of one of the units of which theswitchboard has been built up and shows a front view of the unit. Fig. 2is a bottom plan View of the unit. Figs. 3 and 4 are sections taken onthe line A-A in Fig. 1 showing, respectively, the plug withdrawn andinserted. Fig. is a diagram.

l indicates a plate of Bakelite or the like being enlarged along oneedge andl provided with a recess 2 `for each jack. A metal wire `3, 4preferably of phosphorbronze is fastened to each side inserted and Fig.l shows the position after the insertion into the jack of the plug P,the latter being 'of standard construction, having two cylindrical,conductive parts, divided by an insulating part. As shown in Fig. 4 thewires 3 and `4 are bent out between their fixing points by the in,`

sertion of the plug, a spring contact thus being i established betweenwire and Plug. Also when the plug is inserted into the jack the wires 3and 4 are electrically connected to the contact springs B and 5,respectively. The plate I is supported by a plate 1, which may befastened in a rack. Said plate also supports a call indicator K for theline. By mounting a number ofthe above described units in the rack, andthen connecting the corresponding contact springs inthe units with eachother, mainly by using bare wire connections, a switchboard of thecapacity desired is obtained. With an increase of the number ofsubscribers the switchboard may be enlarged in a simple way by insertingone or several new units into the rack. Fig. 5 is a switching diagramfor a. switchboard made of three units. A, B, C indicate the subscriberslines each of which is connected to the bare wires 3, 4. Eachsubscribers line is provided with four jacks Jo--Ja. 5, 6 indicate thecontact springs in each jack, whereby the corresponding springs in thejacks of the different units, except the springs in the jacks J0, areconnected to each other, so as to form firstly two cord circuits SI andS2 and secondly an operators line T. The contact springs in the upperjack Jo in every unit are connected to a call indicator -Each cordcircuit SI` and S2 is connected tothe supervisory indicator U.` Normallyevery subscribers plug is inserted into the jack J o. When a call isindicated by the call indicator K, the plug is shifted to J1 in order tobe connected with the operators telephone set M, R, Whereupon the plugis inserted into one of the jacks J2, J3 depending upon which one of thecord circuits is idle. f

The invention is of course' not limited to the embodiment abovedescribed but may be modified in several ways within the limits of theinvention idea.

I claim:

1. An arrangement for manual switchboards of the cordless class by whichboth the line wires for each subscriber may be connected t0 cordcircuits, operators telephone set, and the like, by means of a plugcomprising a plurality of jacks for selective reception of said plug,said jacks including two bare wires connected with the line wires ofeach subscriber and adapted to make spring contact with the insertedplug.

2. An arrangement as claimed in claim 1, characterized by the provisionof a body of insulating material supporting a group of jacks related toan individual subscriber and constituting a removable unit.

3. An arrangement as claimed in claimv 1, characterized by the provisionof a call indicator, a body of insulating material supporting theseveral jacks relating to an individual subscriber and forming aremovable unit connected to said call indicator. l

4. An arrangement as claimed in claim 1, characterized by the provisionof a supporting body for said jacks having recesses therein for thereception of a plug, said bare wires extending across said recesses forengagement by the plug. `5. An arrangement as claimed in claim 1,characterized by the provision of an insulating supportl for the jackshaving recesses therein for the reception of a plug, the bare Wiresbeing arranged at' opposite 'sidestof the recessv for" contact withtheinse'rted plug.

6. An arrangement for manual switchboards of the cordless type by whichboth the line wie's. l

characterized in that the wires are arranged on the opposite sides ofthe plate-like support.

, 8. An arrangement as claimed in claim 6, characterized by theprovision of a spring contact the side of the recess opposite thereto.

for each subscriber may be connected `.to cord ,ciizl l cuits, operatorstelephone set and the like," by

means of a plug comprisingraplate-likefsupportz 9. An arrangement formanual switchboards of for 'achsubscriber maybe cnr'ectedt cordcircuits, operator's telephone set and the like by 'means of a plugcomprising a. plurality of jacks forlselectiye reception of said plugs,said jacksA 'including two bare wires connected with the linewiresgofeachsbscriber' for making spring contaictfwitlithe insertedplug, at least one of said 'wires :being'f-so arranged as to be bentoutwardly incident'tqthe irusertion of said plug.

ERIK ISIDOR ENGQUIST.

